Process Challenges for Realization of High Quality Roller Embossing for Patterning Large Area Green Ceramic Substrates

This paper presents our latest achievements in addressing the process challenges in developing large area patterning of green ceramic substrates using hot roller embossing. Micro roller embossing on large area ceramic green substrates was successfully demonstrated by using an electroplated film mold and feeding the sandwiched structure (mold-substrate-supporting plate) through a micro embosser, which consists of top and bottom rollers. Formation of micro patterns on ceramic green substrates over an effective panel size of 150 mm × 150 mm was performed; and micro patterns such as inductors, channels with smallest line width of 50 ¿m were embossed on the ceramic green substrates. This paper also addresses the important process issues for improving embossing fidelity within a pattern unit, as well as the uniformity of unit-to-unit patterns. At lower embossing temperatures, the embossed depth at the center of a pattern unit was found to be lower than that at the edge of the pattern unit. By increasing the embossing temperature, both the embossed depth and the uniformity within a pattern unit were enhanced. The effect of the thickness of green substrates was investigated by increasing the green tapers from 4 layers to 6 layers. The dimensions and locations of the embossed patterns were characterized before and after co-firing, the variations of pattern dimensions and locations were compared with the designed values on the nickel mold. These results will be used as a guideline for actual device design.